UNIVERSITY EXAMINATIONS: 2019/2020
ORDINARY EXAMINATION FOR THE BACHELOR OF SCIENCE
IN SOFTWARE DEVELOMENT
BSD 1104: OPERATING SYSTEMS
DATE: AUGUST, 2019 TIME: 2 HOURS
INSTRUCTIONS: Answer Question ONE and any other TWO
Question 1
a) Explain two basic purposes of Operating System. (4 marks)
b) Define batch systems. (2 marks)
c) Explain thrashing and its cause. (3 marks)
d) Define the virtual memory? What are its advantages? (5 marks)
e) Explain demand paging and its use (4 marks)
f) List the advantages of Contiguous allocation (3 marks)
g) Differentiate between Logical and physical address (3 marks)
h) Differentiate between Segmentation and paging storage (3 marks)
i) Explain three activities that an Operating System does to file management (3 marks)
Question 2
a) Explain the common strategies to select a free hole from a set of available holes (6 marks)
b) Explain the methods used to prevent deadlocks (8 marks)
c) Explain three stages of scheduling (6 marks)
Question 3
a) Explain the requirements that a solution to the critical section problem must satisfy (6 marks)
b) Give the condition necessary for a deadlock situation to arise? (4 marks)
c) Explain the different accessing methods of a file (6 marks)
d) Distinguish external fragmentation from internal fragmentation. (4 marks)
Question 4
a) Briefly explain process lifecycle. (10 marks)
b) Explain why an Operating System would terminate a process. (6 marks)
c) Distinguish between hard real-time system and soft real-time system (4 marks)
Question 5
a) Define process synchronization (2 marks)
b) Explain four types of CPU scheduling. (8 marks)
c) Write short notes on the following: (10 marks)
i. Cooperating process
ii. Independent process
iii. Race condition
iv. Critical section
v. Semaphore
